1. Field of the Invention
This invention relates to an exercise device and, more particularly, to an exercise device having a knee rest and a heel brace to assist in an exercise in which one extends from a kneeling position to an extended position.
2. Description of Related Art
There are numerous exercises which an individual may practice to strengthen muscles and maintain muscle tone. The Royal Canadian Air Force has a well-known exercise regimen with several different exercises required. One of the exercises of this regimen requires a person to start in a kneeling position on his hands and knees, then push his body forward, sliding out along his hands with his arms rigid. The exerciser continues pushing forward until in the prone position with arms extended out beyond head and shoulders and hips lowered to the floor. Then, the exerciser returns to the kneeling position by reversing the sliding action. As one can imagine, this is a very difficult exercise especially for an individual who is not in good physical condition.
The movement of the exercise described above is beneficial for the exerciser's arms, shoulders, upper back, and abdominal muscles. In light of this, others have created exercise devices which assist the exerciser in completing the kneeling-prone-kneeling movement through the use of a biased, wheeled exercise device. For example, the German Patent Applications Offenlegungsschrift No. 2,029,451 to Neubert published Dec. 2, 1971 and No. 2,017,216 to Buchmann published Oct. 28, 1971 disclose wheeled exercise devices which assist the exerciser in the kneeling-prone-kneeling movement described above. In each of these references, the user grasps an axle which rotatably supports one or more wheels. The user hooks his or her feet into stirrups which are connected to the axle by one or more springs or pieces of elastic. The user can push forward from a kneeling position to the prone position by rolling the wheel away from his knees. This movement is resisted by the springs which extend between the wheel and the user's feet.
Tolchin U.S. Pat. No. 1,984,165, issued Dec. 11, 1934 discloses a similar kneeling/prone/kneeling exercise device which incorporates a pair of fixed knee pads which are mounted adjacent a guide rail upon which a trolley rides. The user kneels on the pads, grasps the handle bars of the trolley, and extends forward from the kneeling to the prone position and returns to the kneeling position. A compression spring biases the trolley toward the knee pads.
Another exercise device of this type is disclosed in the Ott U.S. Pat. No. 3,752,475, issued Aug. 14, 1973. Ott describes a wheel rotatably mounted on an axle with a spring or other bias means mounted between the wheel and axle and which resists rotation of the wheel relative to the axle. Therefore, as the user grasps the axle and rolls the device forward, the rotation of the wheel is resisted by the spring bias.
Unfortunately, the exercise devices described above have several significant drawbacks. First, the Neubert, Buchmann, and Ott devices provide no padding for the user's knees. Therefore, use of the device even on a carpeted floor is quite painful for the user's knees. While the Tolchin apparatus does disclose pads for the knees, these pads are fixed with respect to the moving trolley and not adjustable, thereby limiting the usefulness of the device for persons of different size and condition.
Each of the devices discussed above incorporate hooks, straps, stirrups and other attachment means which could easily injure the user. For example, if the user is extended to the fully prone position, the springs of the various devices will be stretched a large amount and exert a large amount of force on the hooks and connections between the springs and the connection to the axle and stirrups. If one of these connections or hooks were to fail under this load, both the failed hook and the spring would become projectiles and could injure the user. Therefore, the elimination of these hooks and interconnections enhances the safety of the product.
Also, the kneeling-prone-kneeling exercise tends to emphasize the muscles of the anterior trunk over those of the posterior trunk and legs. Many people desire to strengthen the muscles of their trunks to support and stabilize their spines. Weak and undertoned trunk musculature often leads to strained back muscles and can lead to increased stress and injury to the disks in the spine between the vertebrae. Well-toned trunk muscles support the spine and help to prevent such injury.
Proper conditioning of the trunk muscles to support the spine requires muscle strength balance; the strength of the many muscles in the trunk must be balanced in order to prevent one or more of the muscles from overpowering and injuring complementary trunk muscles. Many exercises and exercise devices strengthen the abdominal muscles; however, exercising the back muscles without putting undue strain on those muscles is a difficult task. Most exercise devices for exercising the back muscles are bulky, expensive, and suitable only for use at a gymnasium or other facility under proper supervision.
One attempt to design a relatively inexpensive and simple back exerciser is illustrated in the Hall U.S. Pat. No. 5,205,804, issued Apr. 27, 1993. The Hall patent discloses a padded platform having a central, upwardly extending protrusion. A pair of spaced apart rails extend longitudinally from one end of the platform. Parallel, padded ankle and heel bars are elevated slightly above the opposite end of the platform and extend transverse thereto with the heel bar disposed above the ankle bar. An exerciser locks his or her ankles between the padded bars, places his or her abdomen upon the protrusion, and hands upon the rails. By dipping the torso below the rails and then raising the torso above the rails, the exerciser works muscles in the back, legs, and arms. At the exerciser's discretion, the weight load can be redistributed between the back muscles and the arm muscles by reducing or increasing the load supported by the arms.
Unfortunately, the Hall exercise device provides little or no exercise for the abdominal muscles and is not adjustable to limit the stress upon the back muscles. Also, the Hall exercise device is somewhat bulky due to the large vertically extending protrusion for supporting the exerciser's abdomen.
These prior devices, as illustrated above, do not provide balanced exercise for hamstring, quadriceps, gluteus and lower back muscles. Also, most do not support the lower back during the exercise.